1. Field of the Invention
The present invention relates generally to footwear, and in particular the present invention relates to an article of footwear with a reflective outsole.
2. Description of Related Art
Attempts to add provisions for illuminating portions of an article of footwear so that it may be seen in the dark have been proposed. The first category of these disclosures makes use of phosphorescent or ‘glow in the dark’ technology. Van Cleef et al. (U.S. Pat. No. 5,716,723) discloses a glow in the dark shoe sole. The shoe sole includes phosphorescent polymer containing compositions. Likewise, Saruwatari et al. (JP patent number 6,125,801) discloses a light condensing resin molding that is embedded into a transparent shoe sole. The light condensing resin molding is formed by dispersing phosphors such as florescent pigments or fluorescent dyes. Akira (JP patent number 3,280,901) further discloses a shoe coated in a luminous paint. Luminous paints are paints embedded with phosphorescent compounds that may be activated by visible or ultra-violet light. A drawback of these disclosures is that phosphorescent compounds release captured light slowly, resulting in a dim glow, and a far from instantaneous response to incoming light such as a driver's headlights.
Retro-reflective materials reflect incoming light regardless of the angle of incidence. Unlike phosphorescent materials, which emit light slowly, retro-reflective materials emit light almost instantaneously, allowing for a very bright response to incident light. Previous disclosures including retro-reflective materials (often referred to simply as reflective materials) have focused on embedding strips or pieces of a reflective material into an article of footwear. Chiu (U.S. Pat. No. 5,611,156) discloses a reflective shoe having reflective surfaces between a covering layer and an underlying layer. Here, the reflecting layer is disposed along the sides of the outsole. Goldberg et al. (U.S. Pat. No. 6,312,782) discloses an article of footwear that includes discreet shaped colored polymeric objects in a transparent or translucent matrix. The polymeric objects preferably include reflective materials. Both the Goldberg and Chiu designs include the drawback of requiring both the incident and reflected light to pass through a secondary medium (which is different from air). This may reduce the intensity of the reflected light in some circumstances, reducing the ability of the reflective material to alert others to the presence on the wearer of the article of footwear.
Pearson (U.S. Pat. No. 2,607,130) discloses an article of footwear composed of rubber, having light-reflecting areas. The top of the article of footwear comprises a knitted fabric coated on the outside with vulcanized rubber, including a light-reflector mounted on the rubber coating. Lin et al. (U.S. Pat. No. 6,754,985) also discloses an article of footwear including a reflective alert strip that is fixed to the middle sole. These designs include reflectors that have been attached to the upper of an article of footwear, but do not teach a means of adhering reflective materials to the bottom of the outsole. During walking and running motions, the bottom surface of an article of footwear is often the most exposed portion, as viewed from a driver behind the walker/runner.
Along these lines, Tomlinson (U.S. Pat. No. 6,312,782) discloses an article of footwear including a shoe instep reflector. In this design, the reflector may be mounted along the bottom surface of the outsole, disposed close to the ground. A primary drawback to this design is the bulky design of the instep reflector. The reflector has a thickness that requires the instep region of the sole to be depressed in a manner that prevents the reflector from dragging against a bottom surface. Haynes (U.S. Pat. No. 4,233,760) discloses an article of footwear with a light reflective means on the upper portion and on the bottom sole portion of the article of footwear. Along the bottom of the sole potion, the light reflective means includes bars of reflective material that have been embedded in the bottom portion of the outsole. This design is also somewhat cumbersome, in that it requires the outsole to be embedded with solid strips of reflecting material. This may reduce the overall flexibility of the outsole. Furthermore, manufacturing this design requires holes to be cut out of the outsole prior to insertion of the reflective strips. In particular, both the Tomlinson and Haynes designs make it very difficult to cover the large portions of the outsole surface.
There is a need in the art for an outsole including a bottom surface with a large portion that is covered in its entirety with a reflective material. Furthermore, this reflective material should not substantially reduce the flexibility of the outsole.